Making steel castings



Unirse @trarne inerciaG VILLIAM HAINSVORTI-I, Fv PITTSBURG, PENNSYLVANIA.

MAKING erst-2L cae-rises.

PECIFICATION forming part of Letters EatentNo. 284,004, dated August 28, 1853,

r Application filed February QG, ISSB. (No model.)

` To @ZZ whom, it may concern:

Be :it-known that l, WILLIAM HAINsWonri-I,

, a citizen of the United States, residingat Pittsburg, county of Allegheny, State of Pennsylvania, have invented or discovered a new and useful Improvement in Making Steel Castings;`

and I do hereby declare the following to be a full, clear, concise. and exact description thereof, reference being had to the accompanying drawing, making a part of this specification, i

the center or axis of the body of metal filling the mold-cavity, in order to hasten the cooling and crystallization of the inner mass of metal, and also to counteract rapid and unequal centraction of the outer surface by expansion within, thereby preventing unsoundness and distortion by shrinkage, as hereinafter more fully described and claimed.

I hz ve illustrated my invention applied to the casting of a steel roll; but it may be applied to other forms of steel stantially the same way.

In casting steel rolls it is customary to make use of a sand-mold-such, for example, is represented in part in the drawing andlettered A---havingtherein a mold-cavity corresponding to the form of roll Cto be produced,which latter consists of a body portion, c, of cylindrical form, shoulders c, of less diameter than castings in subthe body, and necks c2, of still less diameter than the shoulders.

'The sprue or pouring-hole of the mold-cav'- ity is usually made at one end communicating with the neck, and the opening thus made is enlarged somewhat, as at D, to hold a supply of metal in excess of that required to iill the mold-cavity proper. This cavity I), or the supply of metal therein, is technically known as the sinker-liead,7 and it is designed to afford a supply of metal to fill up any space or opening which might otherwise be formed by shrinkage of the metal in cooling. XVith castings of moderate sizes this method of preventing shrinkage usually accomplishes the desired ness of form. In roll-casting, this difficulty is aggravated by the special form of the article., The neck, being smaller than the body portion, cools and crystallizes first, thus arresting the supply oi' metal from the suiker-head.. Consequently further cooling of the body after the neck is closed results-in more or less contraction, unsoundness, and distortion, such distortion usually taking place at or near the angle of the upper end of .the body and in the upper shoulder, as indicated by dotted lines s. In other forms of heavy castings--such, for example, as are made for subsequent working and reduction into steel shafts for use in heavy machinery-there is great danger of unsoundness, hollow centers, and ruptures, owing to rapid cooling on the exterior and slow protracted cooling in theinner mass of metal. The loss ordinarily sustained in heavy steel castings i'rom difficulties of this nature is considerable, and largely increases both the risks and expense of manufacture.

In applying my invention to roll-casting, molten steel is poured into the mold A, filling its cavity, and also partially filling the sinkerhead cavity, D. Ithen insert in'to the central body of metal a solid and preferably cold body of steel, E, having length a little less than the body c ofthe casting, and thickness, say, about one-third of the full diameter of such body, or less than the diameter of the neck c2.

A core, E, of iron, may be employed instead of steel. Iprefer steel, however, and that ofthe same or approximately the same grade as the molten metal, in order to avoid chemical action, which is liable to arise when different grades of metal are employed, with attendant liberation of gases and formation of blow-holes. This trouble may be obviated in great measure, however, if iron be used, by coating itWith y plumbago or other similar carbonaceous material. This core E is supported and manipulated by means of a comparatively small rod, c, welded or otherwise secured thereto, and having an eye or hook, c', in its free end, in which a cranechain is secured to manipulate IOO the core by power-lift, This rod e may be of iron or steel. For. convenience in welding it to the core I prefer to employ iron, and to coat it with plumbago or equivalent material, to prevent direct contact of molten steel therewith.

lThis body of cold metal E, inserted within the central mass of molten metal,will quickly absorb or take up a large amount of. heat. In this way the whole mass of metal inthe body part c of the roll may be cooled substantially in the same time as the metal in the neck c2. Consequently metal in the sinker-head will be free to settle into the body part of the cavity until the major part of contraction by cooling has taken place, thus preventing contraction in the upper end of the roll to any injurious extent."

In order to secure-the best results, the rod e should, if the pouring end of the casting is smaller than the body below, be comparatively light,l in order to produce but little chilling effect upon the metal in such smaller portion 5 also, the core E should be somewhat shorter than the body part c of the roll; but these proportions may be varied considerably, depending upon the particular form of casting. For example, if the casting be of uniform size throughout, as in casting ingots for shafting,

i the core may also be of similar form. Another important function of the core in this improvement is to occupy the center of the casting with solid metal, which is expanded by heat as the molten metal contracts, thereby counteracting the contracting tendency of the extef rior. Owing to rapid absorption of heat by the core, the greater part of its expansion takes place-soon after its immersion in the molten metal; but the greatest danger to the casting occurs some time after pouring, or after thev metal of the surface has become crystallized.-

By inserting the core after pouring I am enabled to introduce it at such time as to derive the most benefit from its expansion, at the same time keeping in view the beneficial results of uniform crystallization throughout the mass of the casting. If, as practiced heretofore, the core is placed in the mold before pouring, its expansion by heat takes place too soon to be of material benefit, and also danger is incurred of causing the molten metal to spatter or bubble. If the core is inserted after pouring and then withdrawn, as practiced in making tubular castings, it must be withdrawn so will be determined by the size and form ofthe casting, referencebeing had to securing a fused union between the core and molten metal, and

to this end the core -should not be so large as y to chill vthe metal below a degree which will admit of such fusion before or when uniform temperature is secured at and near the surface of the core. The skilled workman can readily make the requisite provision in this respect, knowing the results which it is desired to attain.

rlhis improved method of casting, whether ofrolls or other products, can be applied to advantage either with or without a chill surrounding the mold-cavity.

I claim as my invention- 1. The method herein described of making solid steel castings, consisting in filling the mold-cavity with molten steel, and subsequently inserting in the axis or central mass of fluid metal within the mold a solid metallic core,-

permitting such core to remain and fuse with the previously-poured metal, substantially as and for the purposes set fort 2. The method herein described of casting solid steel rolls having necks of less diameter than the body, consisting in pouring the molten steel into the mold-cavity through the upper neck, and subsequently lowering a solid steel core through the neck or. pouring-openin'g into the axial center of the body part of the mold, and permitting such core to remain therein, the solid and fluid steel being together sufficient in amount to lill the mold-cavity and ll or partially fill the sinker-head, substantially as described.

In testimony whereof I have hereunto set my hand.

wiLLiAM HAinswonTH.

Witnesses: v

. OLIVER FULTON,

C; S. PARKER. 

